Resolve #3114964 "Table is not accessible by screen readers at mobile display size"
Tablesaw fixCellLabels function is fired on page ready. I have changed this to fire when a tablesaw instance is initiated due to asynchronous race condition problem.
Also changed the screenreader only heading display method to table-cell so that screen readers read that as so. display: block means that it loses it's semantic heading properties.
Edited by ian-dev